More than five Hero abilities

I am tring to give a hero more than five hero abilities. I want the unit to pick a number of spells he can use at a time, and when he reaches a place where he can rememorize spells, he can pick other ones. So I need more than five. Anyway to do this without triggers using give ability function? I would like to just use the interface if I could. I might have to go with a spell book deal instead of level up button.

In my opinion, the spell book idea is easiest and most efficent.